Telephone-exchange system



Dec. 1,1925. 1,563,618

E. S. GIBSON TELEPHONE EXCHANGE SYSTEM Filed May 22. 1923 9 Sheets-Sheetl N c Q m Mm D "Q "Q Q Q D c a a U U [1 U M five/70n- Ear/S. 6/?50/2Dec. 1, 1925- 1,563,618

I E. s. GIBSON TELEPHONE EXCHANGE SYSTEM Filed May 22. 1923 9Sheets-Sheet 2 v hven/onfar/ 5. G/fison.

Dec. 1, 1925- 3,618

E. 5. GIBSON TELEPHONE EXCHANGE SYSTEM Filed May 22. 1923 9 Sheets-Sheet3 hven/br: [ar/ 5. G/iso/z All) Dec. 1, 192 1,563,618

E. s. GIBSON TELEPHONE EXCHANGE SYSTEM Filed 1923 9 S W N N m R "1 Dec.1, 1925- 1,563, 18

E. s. mason TELEPHONE EXCHANGE SYSTEM Filed May 22. 1923 9 Sheets-Sheet5 //7ve far/ 8. G/bson E. S. GIBSON TELEPHONE EXCHANGE SYSTEM Dec. 1,1925. 1,563,618

Filed May 22 1923 9 Sheets-Sheet 6 hven/bn- TELEPHONE EXCHANGE SYSTEMFiled May 22. 1923 9 Sheets-Sheet 7 hven/onfar/ 6. Glbson.

a2; a 6/6 622 00/ w 5&5

Dec. 1, 1925. 1.563318 E. S. GIBSON TELEPHONE EXCHANGE SYSTEM 22. 1923 9Sheets-Sheet 8 Patented Dec. 1, 1925.

UNITED. STATES 1,563,518 PATENT OFFICE.

EARL S. GIBSON, 0F RIDGEWOOD, NEEV JERSEY, ASSIGNOR TOWVESTERN ELECTRICCOMPANY, INCORPORATED, OF NEW YGRK, N. Y., A CORPORATION OF NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

Application filed May 22, 1923. .Serial No.- 640,648.

To all whom 2'25 may. concern:

Be it known that L EARL S. GIBsoN, a citizen of the United States,residing at 43 Garfield Place, Ridgewood, in the county of Bergen, Stateof New J ersey, have invented certain new and useful Improvements. inTelephoneExchange $ystems, of which the following is a full, clear,concise, and exact description. I I

Thisinvention relates to telephone exchange systems and especially tosystems employing automatic switching apparatus for setting upconnections. g

The object of theinvention is to provide,

in systems wherev designations are recorded on controlling equipment,improved means for transferring such records from one part of the systemto another.

A feature of the presentinvention relates to tlieprovision of an impulsesending device consisting of relays for creating and sending codeimpulses representing recorded designations from one point to another.

Other features contemplated by this invention will be more thoroughlyunderstood from a consideration of the following detail description and.also from the appended claims.

In. the drawings Figs. 1 to 9, when arranged in the order illustrated inthe diagram of Fig. 10, disclose so much of a telephone exchange systemincorporating the features of the invention as is necessary to athorough understanding thereof.

Fig. 1 illustrates in schematic manner a calling subscribers line andalineswitch of the coordinate type for extending the lines to outgoingtrunks. This figure also shows diagrammatically a sender selector switchof the coordinate type.

Fig. 2 shows a portion of the detailed circuits of one of the trunksoutgoing from the line switch in Fig. 1 and also a diagram of acoordinate group selector switch in which said trunk terminates.

Figs. 3, 4L, 5 and 6 taken together show one of a number of registersender control ling mechanisms which are associable with the trunks bymeans of the sender. selector switch illustrated in Fig. 1.

Fig. 3 illustrates the counting relays and other control relays of thesender. Fig. 4 shows the controlling relays and circuits for sendingcode i1npulses representing recorded designations. Figs. 5 and 6 showfour relay. registers on which designations are recorded under thecontrol or the calling subscribers line.

, Fig. 7 illustrates the incoming end of an inter-oflice trunk circuit.This trunk ap pears in a cord circuit ata manual operators position inthe called office. This figure also shows a called subscriberslineterminating in the manual oflice.

Figs. Sand 9 show a register circuit serv ing thepurpose ofacallindicator.

The line switch 100, the group selector switch 200 and the senderselector switch 110 are of the coordinate type such as shown anddescribed in detail in the application of S. B. Williams, Serial No.596,179, filed Oct. 23, 1922, issued as Patent No- 1,517 ,331, Dec. 2,1924-.

The calling subscriberon initiating a call llfLSdllS line automaticallyextended by Way of the line switch 100 to an idle trunk such as thetrunk 103 terminating in the grou selector or district selector switch200.. At the same time the trunk 103 is associated.

with an idle register sender by means of the sender selector switch 110.Following this the subscriber dials a number of digits which arerecorded on the several registers of the associated sender. Thereafterin any suitable manner the register sender determines the selectiveoperation of the district selector switch 200 and an idle trunk isselected leading to the distant manual oflice in which appears thewanted line.

Inasmuch as the present invention is not concerned with the detailedoperation of the selector switches nor with the manner in which theregister sender exercises its con-' trol over the switches, severalelements have been illustrated in schematic fashion. For a more detailedexplanation of the way in which the operating circuits of the variousswitches function and the manner in which the register senders controlthe selection of trunks, reference is made to the above mentioned patentto Williams.

After a trunk has been selected by the switch 200 in the mechanical.ofiioe leading to the distant manual oflice illustrated in tobringabout the operation of the call .in-

dicator. in order that the operator may be 1 advised of the calledlinenumber. This is accomplished by means of the equipment shown in Fig. awherein the relay device 407 and 408 creates impulses which form codesaccording to the record established on the causes the illumination oflamps before the operator. In case the distant called office is oneinvolving machine switching apparatus for building a connection, codeimpulses would be transferred to a register sender, which in turn, wouldcontrol switches in the called office.

A. detail description will now be given of the establishment of aconnection between a calling line in'the mechanical ofiice such as line101 and a called subscribers line 719 in a distant office involving thetransfer of the record from the first office to the second office.Assume that the numerical part of the designation of the wanted line is2 3 1. The four digits of the numerical designation are recorded on thefour numerical registers of the sender shown in Figs. 5 and 6. Since thecall involves the extension of a connection to a distant office, it maybe desirable in some cases to employ office designations for controllingthe selective switches in the first office to select trunks leading tothe'desired distant office. lVhere office designations are involved theregister sender will have other registers similar to those shown forrecording these designations and for controlling the local switchesaccordingly.

When the calling subscriber initiates the call his line 101 is extendedautomatically through the line switch to the first idle one of a numberof outgoing trunks 102, 103, etc. If the trunk 103 is the first one tobe idle, it is selected and the calling line is extended thereover tothe district selector switch 200. At the same time that the calling lineis extended to the district selector the sender selector switch isoperated automatically and the trunk 103 is connected to the idleregister sender shown in the drawing.

During the operation of the sender selector switch 110 a circuit may beclosed in any suitable manner for the relay 204-. Relay 20a operates andapplies ground potential to the holding or sleeve conductor 111. As soonas the sender selector switch 110 is operated, it may complete a circuitin any suitable manner for the relay 203. Relay 203 closes a substitutecircuit for the slow releasing relay 20d. Relay 203 also extends the tipand ring conductors of the trunk through the sender selector switch 110to the selected sender. An impulse circuit is now traceable from batterythrough the right-hand winding of relay 300 in the sender, contact ofrelay 301, conductor 318, inner left contact of relay 311, thencethrough the selector 110, conductor 220, inner lower contact of relay203, conductor 105, through the line switch 100, over the loop of thecalling line and returning through the line switch 100 to the conductor104, inner upper contact of relay 203, conductor 221, through the switch110, outer left contact of relay 311, conductor 319, contact of relay301, upper winding of coil 302 to ground. Relay 300 closes a circuit forslow release relay 304, which in turn, closes a circuit for relay 310.Relay 310 applies holding ground to the conductor 320 which results inholding circuits for the sender selector switch 110 and for the relay203 in the trunk circuit. Relay 304 completes a circuit from batterythrough the coil 303, left-hand winding of relay 305,

contact of relay to ground. Relay 305, however, does not operate sinceits left winding is shunted by a circuit from battery through the coil303, right contact of relay 300 directly to ground at the contact ofrelay 304. The apparatus is now in condition for receiving the firstseries of im pulses.

The calling subscriber, therefore, manipulates his impulse transmitterto send a series of two impulses representing the first numerical digit.In response to the first opening of the line, relay 300 releases andopens the shunt around the left winding of relay 305 and this latterrelay operates. closes a circuit from battery through its right windingand inner right contact, outer left contact of relay 306, conductor 321to ground at the outer left contact of relay 310. Relay 305 also closesa circuit from battery through the winding of slow to release relay308,outer right contact of relay 305 to the grounded conductor 321.Moreover, relay 305 closes a circuit through the right-hand winding ofrelay 306. Relay 305 also closes a circuit from battery through thewinding of relay 307, outer left contact of relay 305 to the groundedconductor 321. Relay 307 locks through its inner left contact, rightcontact of relay 309 to the grounded conductor 321. Relay 306 operatesand closes a circuit from battery through its left-hand winding andinner left contact to the grounded conductor 321. Relay 306, inaddition, completes a circuit from battery through its right winding andright contact, conductor 322, outer right back contacts of relays 315,314-, 313 and 312, winding of relay 312, outer left back contact ofrelay 313, conductor 323, outer left contact of relay 309, left frontcontact of relay 307, right contact of relay 309 to @the groundedconductor Relay 312, however, does not operate in the above tracedcircuit dueto the shunt main Relay 305 ll O tained by the relay 305 solong as the line circuit is open. When the line circuit is closedfollowing the first opening, relay 300 operates again and replaces theshunt around the left windin of relay 305 and relay 305 immediatelyreleases. Relay305 removes the shunt from around the winding of relay312 and this relay attracts its armatures.

It should be noted at this point that the armatures of the countingrelay 312, which is also true of the remaining counting relays 313, 311, 315 and. 31.6, are so arranged that the inner right contact is closedslightly in advance of the opening of the outer right back contacts. Bythis arrangement a locking of the counting relay is certain to takeplace before the energizing circuit is opened. Immediately that therelay 312 opens its right back contact the circuit throufh the \J rightwinding of relay 306 is opened. Relay 306 is Wounddifferentially. Whilethe flux set up by the left-hand winding of this relay is not sufficientto overcome the flux set up by the right-hand winding to cause a releaseduring the time the circuit of the righthand winding is closed, when thecircuit of the right-hand winding is opened, the effect of thedifferential action between the two windings is a quick release of thearmatures. Relay 312, in operating, locks in a circuit from batterythrough its inner right contact and winding, outer left back contact ofrelay 313 to ground over conductor 323.

In response to the next opening of the line for the second impulse ofthe series, relay 300 releases, relay 305 operates and relay 306 closesa circuit by way of conductor 322, through the outer right back contactof relays 313 and 314, outer right front contact of relay 312, windingof relay 313 outer left back contact of relay.31-1, conductor 323, outerleft contact of relay 309, left front contact of relay 307, rightcontact of relay 309 to the grounded conductor 321. Counting relay 313operates and in the manner above described looks through its inner rightcontact and the outer left back contact of relay .314 to the groundedconductor 323. Relay 313, in operating, opens'the holding circuit ofrelay 312 and this latter relay releases. l After the usual interval haselapsed following the impulse series, slow-to-release relay 308 becomesdeenergized. It will be noted that this relay has its circuitmomentarilyinterrupted by the relay 305'during the sending of pulses, but does notrelease by reason of its slow operating character istic; A circuitis-now closed from ground over conductor 321, through the contact ofrelay 308, right contact of relay 307, inner left contact of relay 309,conductor right back contact of relay 507, Winding of relay 508 tobattery. Relay 508 operates and connects the control leads from thecounting relays to the relays of the register 500. Relay 508 closes a,circuit from battery through its winding and inner upper contact, thenceover conductor 517, winding of relay 309, right contact of relay 307,contact of relay 308 to the grounded conductor 321. Relay 309, however,being shunted by the above traced circuit does not operate at this time.

lVith relay 508 operated a circuit is closed fromground over conductorouter left front contact of relay 313, conductor 325, contact of relay 508, winding of relay 504, winding of relay 502 to battery. Relays 502and 504 look through the inner right contact of relay 1, conductors 518,519 and 520 to ground at the middle right contact of relay 310. Relay502 closes an obvious circuit for relay 507 which operates and looksthrough its inner left contact to the grounded conductor 518. Relay 507opens the shunt around relay 309 and this latter relay energizes inseries with relay 508. Relay 309 opens the holding circuit of relay 307,which in turn, releases and opens the circuit of relays 309 and 508.Relay 503 disconnects the counting relays from the register 500 andrelay 309 again closes the circuit of slow relay 308. It will be notedthat when relay 309 operates in series with relay 508 it opens theholding circuit of the counting relay 313.

The subscriber next operates his dial, and transmits the second seriesconsisting of five impulses. In the manner already explained the firstfour impulses cause the successive operation of counting relays 312,313, 3 4. and 315 and the successive deenergization of relays 312, 313and 314. When the line is opened for the fifth impulse, the circuit overconductor 322 is extended by way of the outer right front contact ofrelay 315, outer right back contact of relay 310, winding of relay 316to ground over conductor 1 323. Belay 316 operates, opens the holdingcircult of relay 315 and locks in a circuit from battery through itsinner right contact and winding to the grounded conductor 323. After aninterval has elapsed following the last impulse, relay 308 releases andthe above traced circuit is extended from ground by way of conductor 321-, right front contact of relay 507, right back contact of relay 511,winding of'relay 512 to battery. Relay 512 operates, connects thecounting relays to the register 501 and closes a circuit through itswinding and contact, over conductor 517, thence as traced through thewinding of relay 309 to ground. telay 309 being shunted does notoperate.

With relay 512 operated a circuit may be tracedfrom' ground overconductor 323, inner left contact of relay-316, inner left contact ofrelay 312, conductor 323, contact of relay 512, winding of relay 509 tobattery. Relay 509 operates and locks through its inner left contact,conductor 521 to the grounded conductor 519. Relay 509 at its outer leftcontact closes an obvious circuit for relay 511 which operates and locksCir r y 606 to battery.

through its inner left contact to the grounded conductor 521. Bela-y 511removes the shunt and permits the relay 309 to operate in series withrelay 512. In the manner above described relay 309 causes the release ofrelay 307 which, in turn, causes the release of relays 309 and Relay 308again operates.

The subscriber manipulates his transmitter to send a thirdseriesconsisting of three impulses. In response to this series relays312, 313 and 311 are operated and relays 312 and 313 are successivelyreleased. After an interval following the series of impulses relay Sreleases and the circuit over conductor 32 1- now leads through theright front contacts of relays 50. and 511, right back contact of relay605, winding of relay d to battery. Relay 00% operates and connects thecounting relays to the register 600 and closes a holding circuit foritself over conductor 51':- and the winding of relay 309 to ground. Therelay 309 being shunted does not operate.

lVith relay 60st operated circuits are completed from the groundedconductor 323, left front contacts of relay 314+, conductors 327 and325, respectively, contacts of relay 00 1, windings of relays 002 and613 to battery. Relays 602 and 613 operate and look through their innerright contacts, conductors 014: and 519 to ground. Relays 002 and 613 atthe outer right contacts close an obvious circuit for relay 605. Relay605 operates and locks through its inner left contact to the groundedconductor 61 1. Relay 605 removes the shunt and permits relay 309 tooperate in series with relay 60 1. Relay 30.9 opens the circuit of relay307 which releases and, in turn, opens the circuit of relays 309 and60a. Relay 604 disconnects the counting relays from the register 600.

Lastly, the subscriber transmits the final series consisting of a singleimpulse and the counting relay 312 is operated. After an internlfollowing the impulse, relay 308 releases and the circuit previously.traced by way of conductor 32 1 now leads from the right front contactsof relays 507, 511 and 005, right contact of relay 007, winding of Relay000 operates, connects the counting relays to the register 001, closes acircuit through its winding and inner upper contact by way of conductor517, through the winding of relay 309 to ground. Relay 309, however,remains deenergized. With relay 606 operated a circuit is'closed by wayof grounded conductor 323, outer left front contact of relay 312,conductor 327, outer right front contact of relay 317, conductor 327,through the contact of relay 606, winding of relay 003 to battery. Relay003 operates and looks through its inner right contact to the groundedconductor 520. Relay 003 closes an obvious circuit for relay 607 which,in turn, operates and locks through its inner left contact and groundedconductor 520. Relay 607 removes the shunt and permits relay 309 tooperate in series with relay 600. Relay 309 unlocks the energizedcounting relay and also opens the circuit of relay 30?. Relay 307, inturn, opens the holding circuit of relays 309 and 606. Relay 606disconnects the counting relays from the register 001.

After the subscriber has set up the record on the sender, the districtselector switch 200 is operated to seize an idle trunk 207 outgoing tothe distant called office. During the operation of the switch 200, relay206 is operated and looks through its inner upper contact, conductor210, upper contact of relay 203 to the grounded conductor 111. Followingthe operation of relay 206, relay 205 is operated by the switch 200 in asuitable manner and locks through its left-hand armature to theconductor 210. After the connection has been extended to the distantoffice the apparatus is placed in condition to transmit code impulsesover the trunk in accordance with the settings of the numericalregisters in Figs. 5 and 6 to operate the call indicator in the distantoflice. When the apparatus is ready for this purpose a circuit iscompleted in any suitable manner for the relay of 113. The manner. inwhich the above mentioned operations take place is shown and described.in detail in the above mentioned patent of S. B. lVilliams.

Relay 413 closes a circuit from battery through the winding of relay100, contact of relay 118, conductor 119, middle left contact of relay607 to ground. Relay 100 operates andlocks through its left contact,conductor 4120 to ground at the inner right contact of relay 310. Relay100 connects the relay 40 1 to the tip and ring conductors of the line,resulting in a circuit as follows: battery through the middle lowercontact of relay 708 in Fig. 7, conductor 723, right winding of relay710, winding of relay 702, inner normal contact of relay 701-, outercontact of relay 700, thence over the tip side of the line through theswitch 200 to the tip conductor of trunk 103, uppermost front contact ofrelay 200, inner right contact of relay 205, V conductor 211, throughthe selector switch 110, conductor 330, inner riglit contact of relay100, outer right contact of relay403, winding of relay 404-, inner rightcontact of relay 103, outer right contact of relay 400, conductor 331,con- Relay 1, seas-1e ductor 212, outer right contact of relay 205,lower front contact of relay 206, thence Over the ring side ot the line,through the inner-back cont-act of relay 7 00, outer normal contact ofrelay 704, left Winding of relay 710 to ground. Relay 710 operates; andcloses a circuit for relay 711. Relay 711 operates and at its outer lcttContact closes a circuit around the relay 702 preventing this relay fromoperating in series with the right Winding of relay 710. Relay 711 alsocloses a circuit from battery through the assignment lamp 713, lowerWinding ct relay 7.12, outer right back contact opt relay 715, innerupper contact o'l relay 712, inner right contact of relay 711 to ground.The lamp 713 illuminates to' advise the operator that a call is awaitingattention on the incoming trunk 207. .Due to the character of relay 712,however, it is not energized through its lower Winding sutficiently toattract its armatures.

The code impulses are sent to the receiving oilice over a full metalliccircuit com' prising both the tip and ring conductors of the line inseries. These impulses may be of either positive or negative polarity dependent upon the pole of battery that is connected to a given side ofthe line circuit. They may also be Weak or strong dependent upon Whethera high or a low resistance is included in the circuit. The impulses arereceived by the relays 800, 801 and 802. The relay 800 is polarized insuch a manner as to respond only When current of positive polarity flowsover the ring side of the line; that is, over the conductor 825'. 01 ispolariz 'ed'in such a manner asto respond to current of the oppositepolarity. Both relays 800 and 801 respond either to strong or Weakimpulses provided the polarity is in the proper direction. Re lay 802responds to strong impulses of either polarity but does not respond toWeak impulses. I

At the time the above traced impulse circuit is closed, relay404 in themechanical oliice also operates and closes a circuit from battery,through the Winding of relay 405, front contact of relay 404 togroundover conductor 420. Relay 405 operates and locks tl'iroughits leftcontact to the con ductor 420. A circuit is now closed from groundthrough the outer right contact of relay 405, conductor 421, thencethrough the outer left contact of relay 507 and the outer left contactof relay and in parallel througl'r the corresponding contacts of relays511, 51.5, 605, 608, over conductor Winding of relay 411 to battery.Relay 411 completes a circuit from ground tl'nroughthe outer rightcontact of relay 405, conductor 421, outer right contact of relay 411,inner right back contact of relay 414,, inner right Contact 0t relay412', outer right contact o'f left-hand windings of relays 415 and 414to battery. Relay 415 operates in this circuit but relay 414 beingmarginal does not receive sufiicient current to energize. 'Re lay 415closes a circuit from battery through theleit-hand windings of relays414 and 415, right-hand Winding of relay 414, in-

ner right contact of relay 415, conductor 421 to ground over conductor420. ltelay 414, however, does not operate since its right-hand Windingcuit above traced. Relay 415 completes a circuit from ground through itsouter right contact,contac't of relay 416, conductor 423, outer rightback contact of relay 513, Winding of relay 514 to battery. Relay 514operates and associates the impulse generating apparatus in Fig. 4 Withthe first register 500' to determine the character of thei mpulses ofthe first digit to be transmitted to the distant oflice'. Relay 514 alsocloses 'a circuit from battery through its Winding and inner lowercontact, conductor 523, Winding of relay 416 to ground at the outerright contact of relay 415. Relay 416 being shunted by the previouscircuit does not operate.

is shunted by the cir relay 413, left back contact of relay 414, i

Returning to the called office, the opera tor observing the illuminationof lamp 713 presses the individual assignment key 716 to associate thecall indicator with the trunk 207 Key 716 closes, a circuit fromloattery through the Winding of relay 821, lower contact, of, relay 712,right winding of re lay 715', upper contact of said key, contact ofrelay 816 to. ground at the right back contact of relay 819. Relay 715operates and locks inacircuit from battery through the Winding of relay821', lower contact of relay 712, windings of relay 715 to'gro'und atits left contact. Relay 715 opens theoriginal circuit of lamp 718 andconnects this lamp in. series .With the interrupter 721. The lampflashes during the period that im' pulses are being received and untilthe operator later inserts the plug of the cord cir cuit in the jack ofit called line. Relay 715 also closes a circuit from battery through theWinding of relay 7 0'0" and in parallel through the winding of relay701, innerright contact of relay 715, winding of relay, 816, left backcontact of relay 819 to ground. Relay 700 operates and extends the tipand ring conductors of the incoming trunk to the conductors 824 and 825,respe ct'ively. N i

l Vhenrela'y 700 operates it opens the circuit including relays 710 and404. Relay 710 releases and opens the circuit of relay 711 which alsode'energi zes. Relay 404, in releasing, completes a circuit from batterythrough the Winding of relay 408, inner right contact otrelay 405,loa'ckcontact of relay 404 to the grounded conductor 420.

Relay 403 operates and locks to the conductor 420.

Relays 407 and 408 at the mechanical office cooperate with each other tomeasure intervals. of time during which code iin-- pulses are producedand propagated over the line circuit to the distant O'l'llCG. Due to thecharacteristics of these relays they operate and release slowly. Relays41 2, 413, 414 and 415 operate in a definite sequence and their functionis to measure a sufficient number of periods of code impulses torepresent each of the different digits. The mechanism is so arrangedthat all digits are sent out withoutinterruption or delay betweendigits.

-With. relay 403 energized a circuit is closed from battery through theresistance 409, winding of relay 407, left back cont-act of relay 408,conductor 425, outer left contact of relay 411, conductor 426 to groundat the outer left contact of relay 403. Relay 407 energizes after aninterval and closes a circuit from batter through the resistance 410,Winding of relay 408, inner lcit contact of relay 407 to the groundedconductor 425. Relay 408 operates after an interval and closes a circuitfrom battery through the Windingof relay 406, normal contact "of saidrelay, outer right front contact of relay 408 to the grounded condrctor425. Relay 406 operates and locks to 'gh its inner left front contact tothe f orndedconductor 425. Relay 408, in opr t n cl'ses acircuit frombattery through the resistance 409, middle right contact ot'relay 408 tothe grounded condnctor 425. This circuit shunts the relay 407 whichcoinniences torelease. After an interval relay 407 becomes deenergizedand a circuit is closed from battery through the re istance 410, rightback contact of relay 407 to the grounded conductor 425. This circuitshunts the relay 408 Which, after an interval, releases itsarinatures.

The interval measured by the release of relays 407 and 408 is used forsending the first inipulse of the code representing the digit in caseany impulse is to be sent. In the present instance, since the registerrelay 503 is not operated, no iinpulse is sent during this period. Whenrelay 408 releases a circuit is closed from battery through theresistance 402, winding of relay 401, outer left contact of relay 407,inner right contact of relay 408, inner right contact of relay 406 tothe grounded conductor 425. Relay 401 operates and locks through itsright contact to the grounded conductor 425.

Relay 408' also closes a circuit from the grounded conductor 425 throughthe outer right back contact of said relay, outer left contact of relayv406, conductor 427, left back contact of relay 41,2, left-hand windingof relay 413, left-hand winding of relay 412 to battery. Relay 413operates but relay 412 being marginal does not energize suiiiciently toattract its arinatures. Relay 413 closes a circuit from battery throughthe left winding of relay 412, left winding of relay 413, right Windingof relay 412, inner right contact of relay 413 to the grounded conductor420. Relay 412, however, does not up crate since its right winding isshunted by the above traced circuit. Relay 413, in op crating, removesthe shunt 110111 the right, winding of relay 414 and this latter relayattracts itsarinatures. Relay 414 closes a circuit from battery throughthe winding of relay 513, lower contact of relay 514, conductor 525,outer right contact of relay 41L to the grounded conductor 420. Relay513 operates, locks through its inner right contact to the groundedconductor 510 and removes the shuntfrom the relay 416. Relay 416operates in series with relay 514.

Relay 408, in releasing, recloses the operating circuit of relay 407,which after an interval, attracts its arniatures and, in turn, closesthe operating circuit ot relay 408. Relay 408 operates after an intervalof time. While relays 407 and 408 are undergoing energizat ion a circuitis closed as follows for transmitting a code impulse over the line: fromground, which represents thepositive pole of battery through the outerright contact of relay 406, conductor 428, inner lett contact of relay411, conductor 420 inner left front contact 0 1' relay 401, inner rightcontact of relay 40-). conductor 330, thence through the selector switch110, conductor 21]., inner right con tact of relay 205, upper troutcontact of relay 206, thence over the tip side of the line, through theouter front contact of relay 700. conductor 824, through the windings orrelays 800, 801 and 802, conductor 825, inner front contact of relay700, thence over the ring side of the line, through the lower frontcontact of relay 206, outer right contact of relay 205, conductor 212,through the selector switch 110, conductor -331, outer right contact ofrelay 400, middle left front contact of relay 401, outer lett contact otrelay 401, conductor 430, outer right back contact of relay 412,conductor 431, contact elf relay 514, inner left contact of relay 50-1,low sistance 527 to the negative pole of battery. Due to the lowresistance a hearv inipulse is transmitted of such a polarity as tocause the operation of relay 801. The impulse being heavy the marginalrelay S02 is also operated. A circuit may now be traced from batterythrough the left windin s oi relays 803. a-nd 804-, left ach contact oi?rclay 803, conductor S27 and contact of relay 801, conductor 828, leftcontact of relay 821. outer left contact of relay to ground. Relay 804operates but relay 503 being lay 808 to battery. Relay 808 operates andcloses a circuit from battery through its winding and the winding ofrelay 807, inner right contact of relay 808 to the grounded conductor829. Relay 807, however, being shunted does not operate at this time.Another circuit is closed from the grounded conductor 828, contact ofrelay 802 outer right back contact of relay 803, inner right backcontact of relay 807, conductor 831, left winding of register relay 900to battery. Relay 900 looks in a circuit through its windings and innerright contact, conductors 901 and 902, right contact of relay 821 toground at the right contact of relay 822.

When relay 408 operates, as above explained, it closes a circuit frombattery through the resistance 402, conductor 433, middle left contactofrelay 406, outer right front contact of relay 408 to the groundedconductor 425. This circuit shunts the relay 401, which thereuponreleases its armatures. Relay 401 at its left contacts opens the impulsecircuit and terminates the impulse being transmitted over the line.Relays 801 and 802 thereupon release. Relay 801 removes ground fromconductor 827 whereby the relay 803' operates in series with relay 804.Relay 803, in operating, opens the above traced shunt around the windingof relay 807. However, this shunt is maintained at the outer rightcontact of relay 804. Relay 408,. in operating, also removes ground fromthe conductor 427 Next the relays 407 and 408 are deenergtzed 1nsuccession in the manner above explained and during the deenergizationmeas ure a period for the transmission of'an impulse over the line incase the register 500 is properly positioned for this'purpose. thepresent case, however, since the relay 505 is not operated, noimpulse,istransmitted to the distant oiiice. Following the deenergi-Zation of relay 408 a circuit is closed from the grounded conductor4'25, outer right back contact of relay 408, left contact of re; lay406, conductor 427, left front contact of relay 412,, left-hand windingof said relay tobattery. This circuit shunts the relay 413 whichthereupon releases. Relay 408, in releasing, also opens the shunt around"relay 401 which attracts its arniatures and terminates the impulseperiod.

Next the relays 407 and 408 are'operated in succession and during thisinterval a circuit is closed from the positive pole of battery overconductor 428, inner left contact of relay 411, conductor 429, innerleft front contact of relay 401, inner right contact of relay 400,thence over the tip side of the line through the windings of relay 800,801 and 802 and returning over the ring side of the line through theouter right contact of relay 400, middle front contact of relay 401,conductor 434, high resistance 528 to the negative pole of battery. Dueto the high resistance 528 relay 802 remains deenergized and due to thepolarity of the impulse, relay 801 operates. Relay lap plies groundpotential to the conductor 827 whereby relay 804 shunted and releaseswhile relay 803 remains looked through its left-hand winding. Relay 804removes the shunt from the relay 807 which still remains shunted due torelay 803. When relay 408 becomes energized it recloses the shunt aroundrelay 401 and this latter relay releases, and opens the impulse circuitcausing the release of relay 80 1. Relay 801 opens the holding circuitof relay 808 'which becomes deenergized. With relay 803 released relay807 operates in series with relay 808. Relay 408 also removes groundfrom conductor 427 whereby relay 412 releases. Relay 412 completes acircuit from battery through the left-hand Winding and left frontcontact of relay 414, outer right con-' tact of relay 413, inner rightcontact of relay 412, inner right front contact of relay 414, innerright contact of relay 415 to ground over conductor 421. This circuitshunts the relay 415 which releases its armatures. Relay 415,inreleasing, opens the holding circuit of.relay 414 which alsodeenergizes. Relay 415 at its outer right contact opens the holdingcircuit of relays 514 and 416'. Relay 514 disconnects the impulsemechanism from the register 500.

The circuit above traced for relays 414 and 415 is again completed andrelay 415 operates while relay 414 being marginal remains deenergized.The apparatus is now in condition to transmit the second digit to thedistant ofiice. Relays 407 and 408 next undergo deenergization insuccession. YVhen relay 4 08 becomes deenergized it opens the shuntaround relay "401 and this relay operates. Relay 408 also closes'theabove traced circuit for relays 412 and 413 and relay 418 operates whilerelay 412 remains deener-' gized. Relay 413, in operating, removes theshunt from relay 414 and this relay operates in series with relay 415.

At the time relay 415 operated it completed. a circuit from groundthrough its outer right contact, contact of relay 416,

conductor 423, outer right front contact of relay 513, outer right backcontact of relay 515, winding of relay 516 to battery. Relay 516operates and closes a circuit through its winding and contact, thenceover conductor 523, through the winding of relay 416 to ground at theouter contact of relay 415. lVhen relay 414 operates a circuit is closedfrom battery through the winding of relay 515, lower contact of relay516, conductor 525, outer right contact of relay 414 to the groundedconductor 421. Relay 515 operates and looks through its inner rightcontact of the conductor 521. Relay 515 also removes the shunt fromrelay 416 and this latter relay operates in series with relay 510.

N ext the relays 407 and 408 undergo operation during which period acircuit is closed from the positive pole of battery over conductor 429,inner left front contact of relay 401, thence over the tip side of theline and returning over the ring side of the line through the middlefront contact of relay 401, conductor 434, high resistance 528 to thenegative pole of battery. This circuit results in a weal; impulse of theproper polarity to operate the polarized relay 801. Relay 801 appliesground potential to the conductor 827' and relay 804 operates in themanner above described. Relay 804 closes a circuit from ground overconductor 829, through the outer right contact of said relay,.left frontcontact of relay 807, left back contact of relay 809, winding of relay810 to battery. Belay 810 operates and closes a locking circuit foritself in series with relay 809 to the grounded conductor 829. Relay809, however, does not operate since it is shunted.

When relay 408 becomes energized it closes the shunt for relay 401 andthis latter relay releases to in turn cause the release of relay 801.Relay 801 removes the shunt from relay 803 and this latter relayoperates in series with relay 804. Relay 408 in operating also removesground potential from conductor 42? whereby relay 412 operates in serieswith relay 413.

The relays 407 and 408 now become deenergized in succession followingwhich, relay 401 operates and relay 418 releases in the mannerdescribed.

Next relays 407 and 408 operate in suc cession and during the intervalrequired for them to attract their armatures a circuit is establishedfrom the positive pole of battery over conductor 429, inner left frontcontact of relay 401, thence over the tip side of the line and returningover the ring side of the line, through the middle and outer left frontcontacts of relay 401, conductor 430, outer right front contact of relay412, conductor 332, upper contact of relay 516, right contact of relay509, low resistance 52? to the negative pole of battery. llhis circuitresults in a heavy impulse causing the operation of relay 802 and alsoof the polarity to energize relay 801. Relay S01 shunts relay 804 whichreleases and removes the shunt from relay 809. Relay however, remainsoperated since the shunt is maintained by relay 803. another circuit isclosed from the grounded conductor throu 'h the contact of relay 802,outer right front contact of relay 803, 'nter right front contact ofrelay 807, outer right back contact of relay S09, conductor 834, leftwinding of relay 903 to battery. Relay 003 locks through its windingsand inner left front contact to the grounded conductor 901. After relays407 and 408 have operated relays 412, 415, 414 and 401 becomedeenergized in the manner hereinbefore described. Relay 415, inreleasing, opens the holding circuit of relays 516 and 416 and theserelays deenergize. Relay 415 now becomes operated in th mannerpreviously described. Relay 415 closes the above traced circuit fromground through its outer right contact, contact of relay 41, overconductor 423, outer right front contacts of relays 513 and 515, outerright back contact of relay 608, winding of relay 009 to battery. Belay609 operates and closes a circuit from battery through its winding andinner ower contact, thence over the conductor 523, winding of relay 410to ground. Relay 410 being shunted does not operate. lheiapparatus isnow in condition to transmit the third or tens digit.

Next, the relays 407 and 4.08 undergo deenergization, during whichperiod, a circuit is closed from the positive pole of battery overconductor 429, middle normal contact of relay 401, thence over the ringside of the line and returning over the tip side of the line through theinner left normal contact of relay 401, conductor 430, left back contactof relay 413, inner right contact of relay 411, conductor 438, innerleft front contacts of relays 513 and 515, inner left back contact ofrelay 008, left contact of relay 602, high resistance 528 to battery.

It will be observed that the impulse circuit above traced throughcontacts of the first relay 602 of register 000 leads through a contactof relay 608 and does not pass through contacts of relay 009. This is topermit the first pulse to be sent immediately and is also true of theother registers. The impulse transmitted in this circuit is weak due tothe high resistance 528 and of such polarity as to operate the relay800. Relay 800 closes a circuit from ground over conductor 828, leftback contact of relay 804, left front contacts of relay 808 and 810,left back contact of relay 812, conductor 835, left winding of relay 904to battery. Relay 904 operates and locks through its windings to thegrounded conductor 902.

After relay 408 hasbecome energized relays 413, 41 4 and 40 1 operate.Relay 401 lnterrupts the impulse being. transmitted and relay 800becomes deenergized.

Next the relays 407 and 408 become operated. During this period acircuit is closed from the positive pole of battery, over conductor 429,inner left front contact of relay 401, thence over the tip side of theline and returning over the ring side of the line through the middle andouter left front contact of relay 401, conductor 430, outer right backcontact of relay 412, conductor 431, contact of relay 609, left contactof'relay 613, low resistance 527 to the negative pole of battery. Aheavy impulse is transmitted in this circuit whereby relays 801 and 802are operated. Relay 801 causes the operation of relay 804 whereupon acircuit is closed from ground over conductor 829, through the outerright contact of relay 804, left front contacts of relay 807 and 809,left back contact of relay 811, winding of relay 812 to battery. Relay812 operates and prepares a circuit for relay 811, but this latter relaybeing shunted does not attract its armatures. Another circuit is closedfrom the grounded conductor 829, through the contact of relay 802, outerright back contact of relay 803, inner right front contacts of relays 807 and 809, inner right back contact of relay 811,

conductor 836, contact of relay 905 to battery. Relay 905 operates andlocks through its inding to the grounded conductor 902.

After relay 408 operates relay 412 energizes and relay 401 becomesdeenergized. Relay 401 interrupts the impulse circuit and relays 801 and802 become deenergized. Relay 80l permits relay 803 to operate in serieswith relay 804.

Next the relays 407 and 408 become deenergized at theend of whichperiod, relay 415 releases and relay 401 operates.

Next relays 407 and 408 become energized and during this period acircuit is closed from the positive pole of battery, over conductor 429,inner left front contact of relay 401, thence over the tip side of theline and returning over the'ring side of the line through the middlefront contact of relay 401, conductor 434, high resistance 528 tobattery. Due to the character of this impulse, relay 801 alone isoperated. Relay 801 closes a shunt for relay 804 and this relay becomesdeenergized. After relay 408 has operated, relays 412, 415, 414 and 401become deenergized. Relay 401 opens the impulse circuit and causes therelease of relay 801. Relay 801 opens the circuit of relay 8 hich i turnp rmi s relay 8 1 90 P- c t n e es ith ts y- 12- R ay imme iate y emi sa above described and closes a circuit over conductor 4 3 th euet theare treat 'eei tae of relays 513, 51 5 and 608, outer right back contactof relay 610, winding of relay 611 to battery. Relay 611 operates andcloses a circuit through its Winding and inner lower contact, conductor523, Winding of relay 416 to ground. Relay 416 being shunted doesnot'operate. The equipment is now in con- 7 "relay 413, inner rightcontact of relay 411,

conductor 438, inner left front contacts of relays 513, 515 and 608,left contact of relay 610, left contact of relay 603, high resistance528 to the negative pole of battery. Due to this impulse relay 800operates and a circuit is closed from ground over conductor 828,1eftback contact of relay 804, left front contacts of relays 808, 810 and812, conductor 838, Winding of relay 906-to battery. Relay 906 operatesand locks to the grounded conductor 902. lVhen relay 408 releases relays413, 414 and 401 become energized. Relay 401 opens the circuit of relay800.

Next the relays 407 and 408 become energized during which period acircuit is closed from the positive pole of battery over con ductor 429,through the inner left front contact of relay 401, over the tip side ofthe line, returning over the ring side of the line, through the middleleft front contact of relay 401, conductor 434, high resistance 528 tothe negative pole of battery. This impulse causes relay 801 to. operatewhereby relay 804v becomes energized. Relay 804 closes a circuit fromgrounded conductor 829,0uter right contact of relay 804, left frontcontacts of relays 807, 809 and 811, inner left back contact of relay813, winding of relay 814 to battery. Relay 814 operates and closes acircuit for itself in series with relay 830, but this latter relayremains deenergized since it is shunted. At the end of a period whenrelay 408 operates relay 412 becomes energized and relay 401 releases,Relay 401 opens the circuit of relay 801 and relay 803 becomesenergized.

Next the relays 407 and 408 become deenergized, at the end 'of whichinterval, relay 413 releases and relay 408 operates.

Lastly, relays 407 and 408 operate. During this period, a circuit isclosed from-the positive poleof battery over conductor 429, inner leftfront contact of relay 401, over the tip side of the line and returningover the ringside of the line through the middle 434, resistance 528 tobattery. Due to left front contact of relay 401, conductor ates andrelay 804 becomes deenergized. ,Aft-er relay 408 becomes energizedrelays 412, 413, 415 and 401 become deenergized. Relay 401 opens theimpulse circuit and relay 801 becomes deenergized to, in turn, cause therelease of relay 803. Relay 803 opens the shunt around relay 813 andthis relay operates in series with relay 814.

Before proceeding with the operations at the distant oliice involvingthe illumination of the operators call indicator, an explanation will begiven of the release of the register sender in the mechanical office.W'Vhen relay 415 releases it opens the circuit of relay 416 and thecircuit of relay 611. Following this, the relay 415 is again operated inthe manner above explained and a circuit is established from groundthrough the outer right contact of relay 415, contact of relay 416,conductor 423, outer right front ,contacts of relays 413, 415, 608 and610,

' relay 304.

low-er back contact of relay 611, conductor 617, winding of releaserelay 311 to bat 'tery. Relay 311'operates and locks to the groundedconductor 320. Relay 311 at its left contacts opens the holding circuitof relay 300, which in turn, opens the circuit of After an intervalrelay 304 releases and opens the circuit of relay 310. Relay 310 removesground from conductors 321, 320, 420 and 520, whereupon the senderselector switch 110 and allenergized relays in the sender and registerare restored to normal. Thus the register sender is disasseciated andmay be taken for use in connection with other calls.

When the sender is released and ground potential is removed fromconductor 320, relay 203 becomes deenergized. Relay 203 releases andextends the tip and ring con ductors of the trunk 103 through to theleft-hand windings of the repeating coil 201..

Relay 202 is now operated in series with the calling line and closes asubstitute holding circuit for the slowrelay 204. In this man nor therelease of the connection is placed under the control of the subscribersswitchhook. Relay 203, in releasing also opens the holding circuits ofrelay" 205 and 200. Relay 206 releases and extends the tip and ringconductors of the trunk 103 through to the right-hand windings ofrepeating coil 201. V

Returning to the call indicator apparatus in the distant ofiice, at thetime. relay 813 operates, a circuit is closed from ground through theouter left contact of said relay, contact of relay 818, winding of relay810 to battery. Relay 810 operates and opens the circuit of relays 700and 701. Relay-700 extends the tip and ring conductors of the trunk 207through to the left-hand windings of repeating coil 720, whereupon t hefollowing circuit is completed: battery, through the middle lowercontact of relay 708, C011- ing of repeating coil 201, winding ofpolarized relay 214, lower right-hand winding of coil 201 and returningover the ring side of the line through the outer normal contacts ofrelay 704, left hand winding of relay 710 to ground.

At the time relay 812 operates it closes an obvious circuit for relay815. lVhen the relay 813 is subsequently energized circuits arecompleted for energizing the numerical lamps in accordance with thedigits recorded on the register relays in Fig. 0. Since the numericaldesignation is 2 5 3 1 the No. 2 thousands lamp 010 is illuminated in acircuit frombattery, through the lower right contact of relay 815,conductor 830, inner right back contact of relay 008, left front contactof relay 000, inner left back contact of relay 000, lamp 010, outerright front contact of relay 000, outer left contact of relay 000, outerright back contact of relay 011, conductor 012, lower left contact ofrelay 815 to the grounded conductor 820. Also a circuit is closed frombattery through the upper right contact of relay 815, conductor 840,lamp 013,1eft hack contact of relay 014, outer right back contact ofrelay 015, left back contact ofrrelay 016, inner left front contact ofrelay 003 to ground over conductor 001. Moreover, another cir cuit isclosed from battery through the outer right contact of relay 814,conductor 841, innerright hack contact of relay 018, left front contactof relay 005, inner left front contact of relay 004, lamp 017, innerleft back contact of relay 018 to the grounded conductor 902. Lastly, acircuit is closed from battery through the right front contact of relay813, conductor S42, inner right back contact of relay 010, left backcontact of relay 920, outer right front contact of relay 006, lamp 020,outer left contact of relay 010 to ground over conductor 002.

The operator reads the number from the lamps of the call indicator,seizes the plug 717 and inserts it in the jack 718 of the called line i710. A circuit is now closed from ground through the sleeve relay 7 25,sleeve of the jack 718, sleeve of plug 717, winding of relay 708, outerright contact of relay 711, which is operated at this time, contact ofrelay 700, inner back contact of relay 706,

Vwinding of relay 707 to battery. A branch lowermost front contactcloses a circuit for the upper winding of relay 712. Relay 712 v lit)operates and opens the circuit of relays 821 and 715. Relay 715disconnects the interrupter 721 from the lamp 713 and this lamp of allilluminated lamps in the call indidigits as is necessary catormechanism.

' Relay 707 operates in the circuit above traced and closes a circuitfrom the source of ringing currentthrough the marginal relay 7 09, lowerfront contact of relay 7 07 ring of the plug and jack, thence over thesubscribers line and returning through the tip and the plug and jack,upper front contact of relay 708, upper contact of relay 707 to ground.lVhen the subscriber res-ponds to the ringing of his bell, the marginalrelay 709 operates, removes the shunt and permits relay 7 06 to becomeenergized. Relay 706 closes a circuit from battery through its innerfront contact and winding and thence to, ground through the sleeve relay725 whereby relay 707 is shunted out and releases. Relay 707 completesthe tip and ring conductors through to the right-hand Windings of therepeating coil 720. Relay 7 05 operates in series with the called lineand closes an obvious circuit for relay 1. Relay 704 serves to reversethe current over the line Which may be used for, any desired purpose.

After the conversation has finished, the

calling subscriber by replacing his receiver on the switchhook opens thecircuit of relay 202, Which in turn, opens the circuit of relay 20 1.After an interval relay 204i releases and removes ground from conductor111 whereby the line switch 100 and the.

district switch 200 become deenergized to restore the connection.

hen the trunk at the mechanical office is released the circuit of relay710 in the distant ofiice is opened and the relay 711 consequentlyreleases. Relay 711 at its outer right contact removes the shunt fromaround the lamp 714:. and this lamp illuminates to advise the operatorthat the connection is no longer required. She, thereupon, Withdraws theplug 717 from the jack 718 and all energized relays associated with thecord circuit are released.

It has thus been explained how the impulse generating equipmentassociated with the register sender in the mechanical otiice creates andtransmits codes of impulses representing digits recorded on theregisters to affect apparatus in the distant exchange- While only thefour numerical digits characterizing the line number have beenconsidered in this system it, of course, Will be understood that thesame mechanism may be employed for transmitting as many other i for theparticular type of syst m con erned,

What is claimed is:

1. Thecombination in a telephone system of a designation recordingmechanism, impulse responsive means for setting up a record on saidmechanism, a second recording mechanism, and, a device consisting ofrelays for originating and sending code impulses to transfer the recordfrom said first mechanism to said second mechanism.

2. The combination in a telephone system of a register controllingsender, means for setting up a designation record on said sender, a.recording mechanism located at a distant point, a two-Wire transmissioncircuit and a device comprising relays for originating and sending codeimpulses over said circuit to transfer the record from said sender tosaid distant recording mechanism.

3. The combination in a telephone system of a register controllingmechanism, means for setting up records on said mechanism, selectiveswitches for extending connections, said switches being controlled bysaid mechanism, recording mechanism, and an impulse sending devicecomprising a plurality of relays for creating and transmitting codeimpulses to transfer records from said controlling mechanism to saidrecording mechanism, 7 i

4. In a telephone system, an oflice'having a designation recordingmechanism, therein, means for setting, up records on said mechanism, adistant oflice having a second recording mechanism therein, and a devicecomprising a number of cooperating relays for originating andtransmitting impulses to transfer a record from the recording mechanismin said first office to the recording mechanism in said second office.

5. In a telephone system, a designation recording mechanism, means forsetting up records 011 said mechanism, a second recording mechanism, atwo-Wire impulse circuit interconnecting said recording mechanism and adeviceconsisting of relays for creating and transmitting code impulsesover said impulse circuit to transfer records from said first recordingmechanism to said second recording mechanism.

6. In a telephone system, a designation recording mechanism, means forsetting up records on said mechanism, a second record ing mechanism, anda pair of intercontrolling relays for measuring and sending codeimpulses to transfer records on said first recording mechanism to saidsecond recording mechanism.

7. In a telephone system, an oflice having switches and recordingmechanism therein, a distant ofiice having a second recording mechanismtherein, means for operating said switches to extend a connection fromthe first to the second oflice, and a device con sisting of relays forgenerating and sending code impulses over said connection to

